NCT01696981

Screening for Colorectal Cancer in Older Patients (PLCO Screening Trial)

Active, enrolled NA Results posted Last updated 23 July 2025

What this trial tests

NA trial testing Screening Questionnaire Administration in Colon Carcinoma in 154,900 participants. Participants enrolled and being followed up; not accepting new ones.

Timeline

16 November 1993

Primary endpoint
21 May 2012

25 March 2026

Quick facts

Lead sponsor	National Cancer Institute (NCI)
Phase	NA
Status	Active, enrolled
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	single
Primary purpose	screening
Enrollment	154,900
Start date	16 November 1993
Primary completion	21 May 2012
Estimated completion	25 March 2026
Sites	1 location across United States

Drugs / interventions tested

• Screening Questionnaire Administration
• Sigmoidoscopy

Conditions studied

• Colon Carcinoma — all drugs for Colon Carcinoma →
• Rectal Carcinoma — all drugs for Rectal Carcinoma →

Sponsor

National Cancer Institute (NCI)

Who can join

Adults 55 to 74, any sex, with Colon Carcinoma or Rectal Carcinoma. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Colorectal Cancer Deaths Primary · Events through 13 years of follow-up or through December 31, 2009; median follow-up 12.1 years.

Colorectal cancer deaths confirmed in participants by a death review committee if available, otherwise by death certificate.

Group	Value	95% CI
Control	341
Colorectal Screening	252

Deaths From All Causes Secondary · Events through 13 years of follow-up or through December 31, 2009; median follow-up 12.1 years.

Deaths from all causes were compared between the colorectal cancer screening arm and the usual care arm.

Group	Value	95% CI
Control	11064
Colorectal Screening	10835

Death Rates From All Causes Secondary · Events through 13 years of follow-up or through December 31, 2009; median follow-up 12.1 years.

Deaths from all causes were compared between the colorectal cancer screening arm and the usual care arm. Rate is the number of deaths divided by person years of follow-up in the study.

Group	Value	95% CI
Control	127.0
Colorectal Screening	124.3

Colorectal Cancer Incidence Secondary · Events through 13 years of follow-up or through December 31, 2009; median follow-up 12.1 years.

Colorectal cancer diagnoses confirmed by medical record abstraction.

Group	Value	95% CI
Control	1287
Colorectal Screening	1012

Colorectal Cancer Incidence Rates Secondary · Events through 13 years of follow-up or through December 31, 2009; median follow-up 12.1 years.

Colorectal cancer diagnoses confirmed by medical record abstraction. Incidence rate (cumulative) defined as colorectal cancer diagnoses divided by person years at risk for colorectal cancer.

Group	Value	95% CI
Control	15.2
Colorectal Screening	11.9

Complications of Diagnostic Evaluation Following a Positive Screening Test Secondary · One year from screening examination

Number of participants who experienced complications during diagnostic work-up of a positive colorectal examination.

When DE Led to Colorectal Cancer Diagnosis

Group	Value	95% CI
Colorectal Screening	58

When DE Did Not Lead to Colorectal Cancer Diag

Group	Value	95% CI
Colorectal Screening	279

Colorectal Cancer Death Rates Primary · Events through 13 years of follow-up or through December 31, 2009; median follow-up 12.1 years.

Colorectal cancer deaths confirmed in participants by a death review committee if available, otherwise by death certificate. Rate is the number of deaths divided by person years of follow-up in the study.

Group	Value	95% CI
Control	3.9
Colorectal Screening	2.9

T0 (Baseline) FSG Screening Results Secondary · T0 (at study entry)

Flexible sigmoidoscopy (FSG) result

Negative

Group	Value	95% CI
Colorectal Screening	42403

Positive

Group	Value	95% CI
Colorectal Screening	15154

Inadequate screen

Group	Value	95% CI
Colorectal Screening	7096

T3/T5 FSG Screening Result Secondary · T3 (three years after entry) or T5 (five years after entry)

Flexible sigmoidoscopy (FSG) result

Negative

Group	Value	95% CI
Colorectal Screening	26694

Positive

Group	Value	95% CI
Colorectal Screening	9818

Inadequate screen

Group	Value	95% CI
Colorectal Screening	5346

Adverse events — posted to ClinicalTrials.gov

Time frame: During each annual screening visit.. Reporting threshold: 0%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Colorectal Screening

Serious: 0/77445 (0%)

Deaths: —

Other adverse events (8 terms — click to expand)

Reaction	System	Colorectal Screening
Dizzy	General disorders	—
Fainted	General disorders	—
Nausea	General disorders	—
Bleeding	General disorders	—
Pain	General disorders	—
Other Adverse Event	General disorders	—
Perforated Bowel	General disorders	—
Anxiety	General disorders	—

Data from ClinicalTrials.gov NCT01696981 adverse events section.

Sponsor's own description

This clinical trial studies whether screening methods used to diagnose cancer of the prostate, lung, colon, rectum, or ovaries can reduce deaths from these cancers. Screening tests may help doctors find cancer cells early and plan better treatment for colorectal cancer.

Publications & conference data

8 peer-reviewed publications reference this trial (live from Europe PMC):

1. Dietary fiber intake and risk of colorectal cancer and incident and recurrent adenoma in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial.
   Kunzmann AT, Coleman HG, Huang WY, Kitahara CM, et al · · 2015 · cited 120× · PMID 26269366 · DOI 10.3945/ajcn.115.113282
2. Long-term anti-inflammatory diet in relation to improved breast cancer prognosis: a prospective cohort study.
   Wang K, Sun JZ, Wu QX, Li ZY, et al · · 2020 · cited 41× · PMID 32821804 · DOI 10.1038/s41523-020-00179-4
3. Fruit and vegetable intakes and risk of colorectal cancer and incident and recurrent adenomas in the PLCO cancer screening trial.
   Kunzmann AT, Coleman HG, Huang WY, Cantwell MM, et al · · 2016 · cited 30× · PMID 26559156 · DOI 10.1002/ijc.29922
4. Association Between Hormone Replacement Therapy and Development of Endometrial Cancer: Results From a Prospective US Cohort Study.
   Liang Y, Jiao H, Qu L, Liu H. · · 2021 · cited 19× · PMID 35111783 · DOI 10.3389/fmed.2021.802959
5. Inflammatory potential of diet and colorectal carcinogenesis: a prospective longitudinal cohort.
   Li Z, Wang K, Shivappa N, Hébert JR, et al · · 2022 · cited 17× · PMID 35136208 · DOI 10.1038/s41416-022-01731-8
6. The contemporary management of prostate cancer.
   Chakrabarti D, Albertsen P, Adkins A, Kishan A, et al · · 2025 · cited 14× · PMID 40572035 · DOI 10.3322/caac.70020
7. Dietary Intake of Tomato and Lycopene and Risk of All-Cause and Cause-Specific Mortality: Results From a Prospective Study.
   Xu X, Li S, Zhu Y. · · 2021 · cited 13× · PMID 34291072 · DOI 10.3389/fnut.2021.684859
8. Gender Differences in Factors Associated with Clinically Meaningful Weight Loss among Adults Who Were Overweight or Obese: A Population-Based Cohort Study.
   Li JB, Qiu ZY, Liu Z, Zhou Q, et al · · 2021 · cited 13× · PMID 33352568 · DOI 10.1159/000512294